在Windows 7上由全屏OpenGL窗口打开的模式对话框未显示 [英] Modal dialogs opened by a fullscreen OpenGL window on Windows 7 are not showing
问题描述
It seems that my problem may be the same as an unanswered related question (OpenGL with GLUT on windows 7, fullscreen mode not showing the message box).
由于我将Win7用作开发环境，并且将其作为我的应用程序的可能目标平台，所以我注意到它们的行为有所下降.
Since I switched to Win7 as a development environment, and a possible target platform for my applications, I noticed a regression in their behaviour.
每当我有一个包含全屏OpenGL上下文的全屏窗口时，应用程序都会在显示模式对话框(例如消息框，文件打开对话框等)时遇到问题
Whenever I have a fullscreen window containing a fullscreen OpenGL context, the applications have problems displaying modal dialog boxes (such as message boxes, file open dialog, etc.)
该窗口仅以WS_POPUP样式创建. GL上下文没什么花哨的. Windows XP一切正常.
The window is just created with WS_POPUP style. The GL context is nothing fancy. And everything is fine with Windows XP.
在Windows 7下，问题在于模式对话框在打开时是不可见的(可能出现在全屏窗口的后面).您必须先Alt-Tab应用程序才能显示对话框.
The problem under Windows 7 is that the modal dialog boxes are invisible at their opening (maybe their appear behind the full screen window). You have to Alt-Tab the application to have the dialogs appear.
这是一个主要问题，因为应用程序似乎在等待用户输入的同时被冻结.
This is a major problem as the application appears to be frozen, while it in fact waits for user input.
有人遇到这种行为吗?有人知道解决方法吗?
Did anyone encounter this behaviour ? Does anyone know a workaround ?
我迅速组成了一个示例测试应用程序；可以在 http://pastebin.com/K4v2NNDs 中找到其源代码.可以在此处.
I've quickly made up a sample test application ; its source code can be found at http://pastebin.com/K4v2NNDs. A simple MSVC8 project can be found here.
PS.我还发布在opengl.org论坛上，对于同时关注这两个问题的人，我们深表歉意.
PS. I've also posted on opengl.org forums, sorry for those of you that follow both.
编辑
由于克里斯(Chris)的评论，我已经在各种事件(例如WM_TIMER或WM_RBUTTONUP)上测试了模式对话框，但是问题仍然存在.
Thanks to Chris comment, I've tested the modal dialog on various events, such as WM_TIMER or WM_RBUTTONUP, but the problem is still there.
我也用'DWM_EC_DISABLECOMPOSITION'调用了'DwmEnableComposition'只是为了检查:问题仍然存在.
I've also called 'DwmEnableComposition' with 'DWM_EC_DISABLECOMPOSITION' just to check : problem still there.
我还通过用DirectX替换OpenGL位对应用程序进行了测试，这样，一切都可以按预期进行……这确实是OpenGL引起的问题.
I've also tested the application by replacing the OpenGL bits by DirectX, and this way everything works as expected... It's really OpenGL causing the problem.
(更新后的pastebin http://pastebin.com/Rq1Ehm3w 和我的便签本)
(updated pastebin http://pastebin.com/Rq1Ehm3w and my scratchpad)
编辑
该问题在Windows 8上也存在.
The problem also exists on Windows 8.
推荐答案
A workaround has been posted on opengl.org by Joseph Steel, so, for reference I put it here as well :
我为此问题找到的解决方案是确保窗口的像素格式使用WGL_SWAP_COPY_ARB交换方法，而不是WGL_SWAP_EXCHANGE_ARB.
The solution I found for this problem was to ensure that the pixel format for the window uses the WGL_SWAP_COPY_ARB swap method rather than the WGL_SWAP_EXCHANGE_ARB.
我注意到，必须使用'wglChoosePixelFormatARB'来获取像素格式.
I've noted that one must use 'wglChoosePixelFormatARB' to obtain the pixel format.
我尝试使用带有'PFD_SWAP_COPY'标志的经典'ChoosePixelFormat'，但是它不能在我的系统上运行(Win7 x64 + NVidia GeFo 9600GT v196.21)，因为它总是返回带有'PFD_SWAP_EXCHANGE'的像素格式
I tried with the classic 'ChoosePixelFormat' with the 'PFD_SWAP_COPY' flag, but it does not work on my system (Win7 x64 + NVidia GeFo 9600GT v196.21) as it always returns me a pixel format with 'PFD_SWAP_EXCHANGE' instead.
我对结果只满意一半，因为它使我的显示器有些撕裂，但至少可以起作用！
I'm only half-happy with the results, as it introduces some tearing in my display, but as least it works !
For reference, I've updated my test source code.
EDIT，2013年12月
至少在我的系统(笔记本电脑，Optimus GeForce 650M)上，此解决方法不再起作用. WGL_SWAP_COPY_ARB已设置，但不显示模式对话框.到目前为止，似乎创建具有1个像素边框的窗口(将WS_BORDER添加到WS_POPUP样式)确实可以解决问题，并且可以防止进入全屏"模式.
This workaround does not work anymore, at least on my system (laptop, Optimus GeForce 650M). The WGL_SWAP_COPY_ARB is setup but the modal dialog does not show. So far, it seems that creating the window with a 1 pixel border (adding WS_BORDER to WS_POPUP style) does the trick, and prevents entering 'fullscreen' mode.
这篇关于在Windows 7上由全屏OpenGL窗口打开的模式对话框未显示的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
